Nanoporous CuCo2O4 nanosheets as a highly efficient bifunctional electrode for supercapacitors and water oxidation catalysis

Efficient and low‐cost multifunctional electrodes play a key role in improving the performance of energy conversion and storage devices. In this study, ultrathin nanoporous CuCo2O4 nanosheets are synthesized on a nickel foam substrate using electrodeposition followed by air annealing. The CuCo2O4 nanosheet electrode exhibits a high specific capacitance of 1473 F g─1 at 1 A g─1 with a capacity retention of ∼93% after 5000 cycles in 3 M KOH solution. It also works well as an efficient oxygen evolution reaction electrocatalyst, demonstrating an overpotential of 260 mV at 20 mA cm─2 with a Tafel slope of ∼64 mV dec─1. in 1 M KOH solution, which is the lowest reported among other copper-cobalt based transition metal oxide catalysts. The catalyst is very stable at >20 mA cm─2 for more than 25 h. The superior electrochemical performance of the CuCo2O4 nanosheet electrode is due to the synergetic effect of the direct growth of 2D nanosheet structure and a large electrochemically active surface area associated with nanopores on the CuCo2O4 nanosheet surface

Engineering of Interface and Bulk Properties in Cu2ZnSn(S,Se)4 Thin-Film Solar Cells with Ultrathin CuAlO2 Intermediate Layer and Ge Doping

Recently, kesterite-based absorbers and related compounds have been considered as promising eco-friendly light absorber materials for thin-film solar cells (TFSCs). However, the device performances of kesterite-based TFSCs are limited because of the formation of defects and poor interfacial properties. In this study, we developed a strategic approach to improve the device performances of Cu2ZnSn­(S,Se)4 (CZTSSe) solar cells using back-interface passivation of the absorber layer and further reduced the formation of defects through Ge doping. The application of CuAlO2 (CAO) as an intermediate layer near the back interface efficiently improves the grain growth and minimizes the detrimental Mo­(S,Se)2 thickness. In addition, the Ge nanolayer deposited over the CAO layer improves the absorber bulk quality, effectively suppresses the defect density, and reduces the nonradiative carrier recombination losses. As a result, the short-circuit current density, fill factor, and power conversion efficiency of the champion device with the CAO and Ge nanolayer improved from 31.91 to 36.26 mA/cm2, 0.55 to 0.61, and 8.58 to 11.01%, respectively. This study demonstrates a potential approach to improve the performances of CZTSSe TFSCs using a combination of back-interface passivation and doping

High-speed, low-bias operated, broadband (Vis-NIR) photodetector based on sputtered Cu2ZnSn(S, Se)(4) (CZTSSe) thin films

Photodetectors have large applications in the current ongoing pandemic. These can be used to study the growth of viruses where depending upon the concentration the light intensity will be reduced. Since the viruses grow very fast therefore a device with very low response time as well as quick recovery will be useful for this study. If the device can be made from the non-toxic materials and sizes are quite small, they can be used for in vitro studies as well. Kesterite Cu2ZnSn(5, Se)(4) (CZTSSe) thin film can be deposited over flexible substrates. The detectivity of even very small area device is very high with ultra-small response and recovery time. The CZTSSe PD exhibited excellent broadband (Vis-NIR) photoresponse, high responsivity of 18.0 mA.W-1, a fast rise time of 82 ms, and a decay time of 97 ms, as well as high detectivity (similar to 10(9) Jones) with favorable self-powered characteristics. This work suggests significant scientific insights for photoconductivity properties of emerging kesterite CZTSSe thin-film materials for broadband, low-cost, high-efficiency next-generation thin-film photodetectors for various optoelectronic applications including diagnostic

Nanoscale Rear-Interface Passivation in Cu2ZnSn(S,Se)4 Solar Cells through the CuAlO2 Intermediate Layer

The present work demonstrates that the addition of p-type CuAlO2 (CAO) as an intermediate layer between molybdenum (Mo) and the absorber rear interface efficiently improves the Cu2ZnSn(S,Se)4 (CZTSSe) device performance. The efficacy of the intermediate layer is analyzed through sputtering the CAO nanolayer at different deposition times on top of the Mo layer. The addition of an ultrathin CAO nanolayer improved the absorber bulk quality with the formation of compact and larger crystalline grains. Furthermore, the CZTSSe device with an optimum deposition time (154 s) of the CAO nanolayer successfully reduced the Mo(S,Se)2 layer thickness from ∼50 to ∼25 nm. This reduced Mo(S,Se)2 layer thickness results in the reduced series resistance (Rs) in the device providing improvement in the overall device performance. The short-circuit current density (JSC) and the power conversion efficiency of the device with the CAO nanolayer increased from 33.48 to 35.40 mA/cm2 and from 9.61 to 10.54%, respectively, compared to a reference device. © 2021 American Chemical Society.1

Proceedings of National Conference on Relevance of Engineering and Science for Environment and Society

This conference proceedings contains articles on the various research ideas of the academic community and practitioners presented at the National Conference on Relevance of Engineering and Science for Environment and Society (R{ES}2 2021). R{ES}2 2021 was organized by Shri Pandurang Pratishthan’s, Karmayogi Engineering College, Shelve, Pandharpur, India on July 25th, 2021. Conference Title: National Conference on Relevance of Engineering and Science for Environment and SocietyConference Acronym: R{ES}2 2021Conference Date: 25 July 2021Conference Location: Online (Virtual Mode)Conference Organizers: Shri Pandurang Pratishthan’s, Karmayogi Engineering College, Shelve, Pandharpur, India

Worldwide Disparities in Recovery of Cardiac Testing 1 Year Into COVID-19

BACKGROUND The extent to which health care systems have adapted to the COVID-19 pandemic to provide necessary cardiac diagnostic services is unknown.OBJECTIVES The aim of this study was to determine the impact of the pandemic on cardiac testing practices, volumes and types of diagnostic services, and perceived psychological stress to health care providers worldwide.METHODS The International Atomic Energy Agency conducted a worldwide survey assessing alterations from baseline in cardiovascular diagnostic care at the pandemic's onset and 1 year later. Multivariable regression was used to determine factors associated with procedure volume recovery.RESULTS Surveys were submitted from 669 centers in 107 countries. Worldwide reduction in cardiac procedure volumes of 64% from March 2019 to April 2020 recovered by April 2021 in high- and upper middle-income countries (recovery rates of 108% and 99%) but remained depressed in lower middle- and low-income countries (46% and 30% recovery). Although stress testing was used 12% less frequently in 2021 than in 2019, coronary computed tomographic angiography was used 14% more, a trend also seen for other advanced cardiac imaging modalities (positron emission tomography and magnetic resonance; 22%-25% increases). Pandemic-related psychological stress was estimated to have affected nearly 40% of staff, impacting patient care at 78% of sites. In multivariable regression, only lower-income status and physicians' psychological stress were significant in predicting recovery of cardiac testing.CONCLUSIONS Cardiac diagnostic testing has yet to recover to prepandemic levels in lower-income countries. Worldwide, the decrease in standard stress testing is offset by greater use of advanced cardiac imaging modalities. Pandemic-related psychological stress among providers is widespread and associated with poor recovery of cardiac testing. (C) 2022 The Authors. Published by Elsevier on behalf of the American College of Cardiology Foundation